西安城区夏季地面臭氧浓度变化特征分析

于2013年夏季,对西安城区10个大气监测点进行了地面大气中O3及其前体物(NOx、CO)连续在线观测,观测结果分析表明:夏季O3小时浓度平均值范围为39.03~93.06μg/m3,且其浓度呈现由东北至西南方向逐渐升高的空间分布特征。O3小时浓度分布呈明显的单峰形式,15:00左右达到峰值;NOx、CO浓度呈较明显的双峰分布,CO较NOx的浓度波动较为平缓。O3日均浓度与温度、太阳辐射呈正相关,而与相对湿度呈负相关关系,且受温度、太阳辐射的影响更加显著。

ANALYSIS ON VARIATION CHARACTERISTICS OF SURFACE OZONE CONCENTRATION IN URBAN AREA OF XI'AN IN SUMMER

In the summer of 2013，a constant real-time survey of O3 and its precursors ( NOx and CO) near the ground was conducted at ten air quality monitoring sites within Xi'an city． The results showed that the hour average concentration of O3 in the summer was between 39. 03 μg /m3 and 93. 06 μg /m3 ，and the concentration increased from northeast to southwest direction． In addition， the hour concentration distribution of O3 exhibited a distinct mono-peak pattern and the O3 concentration reached the peak at 15: 00 in the afternoon; while the distribution of NOx and CO concentration showed a doublepeak phenomenon， and the CO concentration changed gently compared with NOx concentration． The daily average concentration of O3 was positively associated with the temperature and solar radiation，and negatively associated with relative humidity． The temperature and solar radiation had remankable impacts on the average daily O3 concentration．